Two cases of leptospirosis are described in soldiers who fell into a river together. One developed Weil's disease due to icterohaemorrhagiae serogroup and the other "Mud-Fever" due to grippotyphosa serogroup. The organisms were initially cultured in standard blood culture media. There were six cases of leptospirosis in BAOR in the 10 years to 1980 giving an incidence 10 times greater than in the civil population of UK and West Germany. Leptospirosis is an occupational disease of soldiers in BAOR and the health risks of fresh water immersion should be publicised.